Physiological role

The book takes in consideration some dehydrogenases, enzymes with different functions in the cells by using different substrates, such as hydroxysteroid dehydrogenases, aldehyde dehydrogenases, glucose-6-phosphate dehydrogenase, pyruvate dehydrogenase complex, glutamate dehydrogenase, succinate dehydrogenase. They are examined from the following points of view: biochemistry, physiological functions and role in some diseases and in the development of tumours. For these reasons, the book is divided into three sections: 1. Dehydrogenases and cancer 2. Dehydrogenases and some diseases 3.

In plants, fatty acids (FA) are subjected to various types of oxygenation
reactions. Products include hydroxyacids, as well as hydroperoxides, epox-ides, aldehydes, ketones and a,x-diacids. Many of these reactions are cata-lysed by cytochrome P450s (P450s), which represent one of the largest
superfamilies of proteins in plants.

Physiology plays a major role in the scientific foundation of medicine and other
subjects related to human health and physical performance. Pharmacology is the
science which deals with the effects of drugs on living systems and their use in the
treatment of disease. This book is designed to enhance students’ understanding of
physiology and pharmacology via a series of case studies involving human disease
and its treatment.
Traditional university teaching methods focus on informing students in terms of
physiological and pharmacological theory.

Steroids - From Physiology to Clinical Medicine covers contemporary basic science on steroids research, along with steroids practical application in clinical medicine. We start by describing physiological and pathophysiological roles of steroids, with reference to production and action of gonadal steroids, role of steroid sulfonation, sex specific and steroids-dependent mechanism of hippocampal function, and the hydroxysteroid dehydrogenases for the modulation of tissue glucocorticoid availability.

This study was aimed at investigating the physiological role of ferredoxin-glutamate synthases (EC 1.4.1.7), NADH-glutamate synthase (EC 1.4.1.14)
and carbamoylphosphate synthetase (EC 6.3.5.5) in Arabidopsis. Pheno-typic analysis revealed a high level of photorespiratory ammonium, gluta-mine⁄glutamate and asparagine⁄aspartate in theGLU1mutant lacking the
major ferredoxin-glutamate synthase, indicating that excess photorespiratory
ammonium was detoxified into amino acids for transport out of the veins....

Alternative oxidase (AOX) is a ubiquitous respiratory enzyme found in
plants, fungi, protists and some bacterial species. One of the major ques-tions about this enzyme is related to its metabolic role(s) in cellular physi-ology, due to its capacity to bypass the proton-pumping cytochrome
pathway, and as a consequence it has great energy-wasting potential.

The physiological role of sulfoquinovosyl diacylglycerol (SQDG) in photosynthesis was investigated with a SQDG defective mutant (hf-2) of Chlamydomonas reinhardtii that did not have any detectable amount of SQDG. The mutant showed a lower rate of photosystem II (PSII) activity by 40% and also a lower growth rate than those of the wildtype. Results of genetical analysis of hf-2 strongly suggest that the SQDG defect and the lowered PSII activity are due to a single gene mutation.

The physiological role of a bifunctional enzyme,
3,4-dihydrocoumarin hydrolase (DCH), which is capable of
both hydrolysis of ester bonds and organic acid-assisted
bromination of organic compounds, was investigated.
Purified DCH fromAcinetobacter calcoaceticusF46 cata-lysed dose- and time-dependent degradation of peracetic
acid. The gene (dch) was cloned from the chromosomal
DNA of the bacterium.

This chapter students will be able to: List the basic functions of the nervous system; explain the structural and functional divisions of the nervous system; list the types of neuroglia and cite their functions; define neuron, describe its important structural components, and relate each to a functional role;...

Chapter 13 (part d) provides knowledge of motor endings and motor activity. In this chapter, students will be able to compare and contrast the motor endings of somatic and autonomic nerve fibers, outline the three levels of the motor hierarchy, compare the roles of the cerebellum and basal nuclei in controlling motor activity.

In this chapter, students will be able to understand: Describe the events involved in the stimulation of photoreceptors by light, and compare and contrast the roles of rods and cones in vision; compare and contrast light and dark adaptation; trace the visual pathway to the visual cortex, and briefly describe the steps in visual processing.

We live in the age of biology—the human and many other organisms’
genomes have been sequenced and we are starting to understand the
function of the metabolic machinery responsible for life on our planet.
Thousands of new genes have been discovered, many of these coding for
enzymes of yet unknown function. Understanding the kinetic behavior
of an enzyme provides clues to its possible physiological role. From
a biotechnological point of view, knowledge of the catalytic properties
of an enzyme is required for the design of immobilized enzyme-based
industrial processes.

Arterial CO2 tension is a powerful modulator of cerebral vascular calibre, CBF and ICP (12-15.)
While the mechanisms are incompletely understood, CO2 relaxes pial arterioles by
interactions between the endothelium, vascular smooth muscle, pericytes, adjacent neurons
and glial cells. Studies supported that cerebral vessels are sensitive to changes in
extracellular pH, rather than a direct response to CO2 or bicarbonate. In the limits of
physiological PaCO2, 20-60 mmHg, the relationship between PaCO2 and CBF is linear.

The growth of magnetic resonance imaging (MRI) as a tool for studying brain function, as opposed
to its more traditional role as a tool for studying brain anatomy and pathology, has been quite
remarkable over the past decade. This has been driven in large measure by an appreciation of the
considerable potential for functional magnetic resonance imaging (fMRI) to increase our understanding
of how the human brain works, both in the normal and diseased states.

This chapter describes the physiological role and pathophysical consequences of histamine release
and provides a summary of the therapeutic use of histamine H1-receptor antagonists. H2-receptor
antagonists are discussed in detail in Chapter 37: Agents Used for Control of Gastric Acidity and
Treatment of Peptic Ulcers and Gastroesophageal Reflux Disease in the context of prevention and
treatment of peptic ulcers, their principal therapeutic application.

WATER PLAYS A CRUCIAL ROLE in the life of the plant. For every gram of organic matter made by the plant, approximately 500 g of water is absorbed by the roots, transported through the plant body and lost to the atmosphere. Even slight imbalances in this flow of water can cause water deficits and severe malfunctioning of many cellular processes. Thus, every plant must delicately balance its uptake and loss of water. This balancing is a serious challenge for land plants. To carry on photosynthesis, they need to draw carbon dioxide from the atmosphere, but doing so exposes them to...

Nature has created numerous elegant living systems, including the human, based on the
hierarchical functional units—molecule, cell, tissue, and organ. A living system develops
through a long evolutionary process, during which the system undergoes genotypic and
phenotypic changes in response to environmental simuli.

This book presents basic and advanced principles underlying the multivalent
interactions that are prevalent in biological systems. To illustrate important or
complex concepts, the book provides up-to-date examples of synthetic multivalent
molecules, their design, and their biological benefits. Functional roles
displayed by such molecules of both natural and synthetic origin are well
documented in biology, where they exert unique and crucial activities at a
level not readily achievable by monovalent molecules.